Discuss: end of life scheduling for outdated templating

I'd like to open a discussion about how we notify users of removing functionality.

As a specific example, Microsoft stopped support of .NET 4, 4.5, and 4.5.1 in January 2016. We still maintain 4/4.5 options officially even though 4.5.2 is an in place replacement to the other versions. Removing any amount of conditionals in the C# templates would improve maintainability.

While I understand that users often have reasons for requiring EOL'd versions, removing these from official maintenance doesn't necessarily remove a user's ability to create a custom template (or refer to a template version prior to template support being removed). Since these unmaintained framework versions no longer receive security updates, I feel like maintaining them may require a warning that these are no longer maintained by Microsoft.

What are the thoughts about creating a template archive repository?